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GCN Circulars

GCN Circulars are rapid astronomical bulletins submitted by and distributed to community members worldwide. They are used to share discoveries, observations, quantitative near-term predictions, requests for follow-up observations, or future observing plans related to high-energy, multi-messenger, and variable or transient astrophysical events. See the documentation for help with subscribing to or submitting Circulars.

Search for Circulars by submitter, subject, or body text (e.g. 'Fermi GRB').
To navigate to a specific circular, enter the associated Circular ID (e.g. 'gcn123', 'Circular 123', or '123').
Advanced Search

To narrow the search results, use advanced search syntax. This allows for specifying which circular field to search (submitter, subject, and/or body). For additional information, refer to the advanced search documentation.

Advanced Search Examples (click to copy):

subject:"Swift"
body:"GRB"
submitter:"Judith Racusin"
  1. IceCube-221223A - IceCube observation of a high-energy neutrino candidate track-like event
  2. GRB 221221A: AGILE detection
  3. Fermi GRB 221221A: Global MASTER-Net observations report
  4. GRB 221221A: Fermi GBM Final Real-time Localization
  5. GRB 221218A: 3.6m DOT optical upper limit
  6. IceCube-221216A: No Candidate Counterparts from the Zwicky Transient Facility
  7. GRB 221216A: Detection by VZLUSAT-2
  8. GRB 221218A: MITSuME Akeno optical upper limits
  9. GRB 221218A: BOOTES-4/MET and OSN optical upper limits
  10. GRB 221218A: KAIT Optical Upper Limit
  11. IceCube-221210A: BOOTES-4/MET and Lijiang 2.4-meter Telescopes Optical Observations
  12. GRB 221215A: Fermi GBM Detection
  13. GRB 221218A: a long GRB detected by INTEGRAL
  14. Integral GRB221218.34: Global MASTER-Net observations report
  15. Fermi-LAT gamma-ray observations of IceCube-221216A
  16. IceCube-221216A: Upper limits from a search for additional neutrino events in IceCube
  17. GRB 221216A: Swift/UVOT Upper Limits
  18. GRB 221216A: Fermi GBM observation
  19. GRB 221216A: Swift-XRT refined Analysis
  20. Fermi-LAT gamma-ray observations of IceCube-221210A
  21. IceCube Alert 221216.25: Global MASTER-Net observations report
  22. GRB 221216A: AKO Upper Limit
  23. GRB 221215A: Swift-XRT observations
  24. GRB 221216A: Enhanced Swift-XRT position
  25. Swift GRB 221216A: Global MASTER-Net observations report
  26. GRB 221216A: Zadko observatory - Gingin optical observations
  27. GRB 221216A: Nanshan/NEXT optical upper limits
  28. GRB 221216A: Swift detection of a burst
  29. GRB 221216A: Fermi GBM Final Real-time Localization
  30. IceCube-221216A - IceCube observation of a high-energy neutrino candidate track-like event
  31. Fermi trigger No 692760884: Global MASTER-Net observations report
  32. GRB 221215A: Swift ToO observations
  33. GRB 221215A: Swift/BAT-GUANO arcminute localization
  34. Konus-Wind detection of GRB 221209A
  35. Fermi GRB 221215B: Global MASTER-Net observations report
  36. IPN triangulation of GRB 221209A (long)
  37. GRB 221215B: Fermi GBM Final Real-time Localization
  38. Fermi Gamma-ray Burst Monitor trigger 692760884/221215066 is not a GRB
  39. Swift GRB221215.15: Global MASTER-Net observations report
  40. Fermi trigger No 692713692: Global MASTER-Net observations report
  41. GRB 221215A: Fermi GBM Final Real-time Localization
  42. Swift Trigger 1144538 is not a GRB
  43. Fermi Gamma-ray Burst Monitor triggers 692721536/221214610 and 692713692/221214520 are not GRBs
  44. Konus-Wind detection of a burst from SGR 1935+2154 on 2022 December 13
  45. Fermi trigger No 692607435: Global MASTER-Net observations report
  46. GRB 221209A: CALET Gamma-Ray Burst Monitor detection
  47. IceCube-221210A: Upper limits from a search for additional neutrino events in IceCube
  48. GRB 221212A: Fermi GBM Final Real-time Localization
  49. Fermi GRB 221211A: Global MASTER-Net observations report
  50. GRB 221208A: AstroSat CZTI detection
  51. GRB 221211A: Fermi GBM Final Real-time Localization
  52. IceCube-221210A - IceCube observation of a high-energy neutrino candidate track-like event
  53. IceCube Alert 221210.36: Global MASTER-Net observations report
  54. GRB 221009A: MuSCAT3 observations
  55. GRB 221209A: AstroSat CZTI detection
  56. GRB 221210A: Fermi GBM Final Real-time Localization
  57. GRB 221209B: Fermi GBM Final Real-time Localization
  58. GRB 221209A: Fermi GBM observation
  59. GRB 221203C: AstroSat CZTI detection
  60. GRB 221209A: BALROG localization (Fermi Trigger 692257829 / GRB 221209243)
  61. GRB 221209A: Fermi GBM Final Real-time Localization
  62. GRB 221206B: Fermi GBM observation
  63. GRB 221206B: Swift-XRT observations
  64. GRB 221206B: Detection by GRBAlpha
  65. GRB 221206B: Swift/BAT-GUANO candidate arcminute localization
  66. GRB 221206B: Swift ToO observations
  67. Swift/BAT trigger #1143281 is not a GRB
  68. GRB 221206C: Fermi GBM Final Real-time Localization
  69. GRB 221206B: Fermi GBM Final Real-time Localization
  70. GRB 221206A: Fermi GBM Final Real-time Localization
  71. GRB 221205A: Fermi GBM Final Real-time Localization
  72. Swift GRB221204.45 AKO Upper Limit
  73. GRB 221202B: Detection by VZLUSAT-2
  74. Swift GRB221204.45: Global MASTER-Net observations report
  75. GRB 221203B: Fermi GBM Final Real-time Localization
  76. GRB 221202A: Swift/UVOT Detection
  77. GRB 221202A: Swift-BAT refined analysis
  78. GRB 221202A: VLT/FORS2 Afterglow Discovery
  79. GRB 221201A: Swift-BAT refined analysis
  80. GRB 221203A: Fermi GBM Final Real-time Localization
  81. GRB 221201A: Fermi GBM observation
  82. GRB 221202A: Swift-XRT refined Analysis
  83. GRB 221202A: LCOGT Optical Upper Limits
  84. GRB 221202A: Enhanced Swift-XRT position
  85. GRB 221202A: MeerLICHT upper limits
  86. GRB 221202B: Fermi GBM Final Real-time Localization
  87. GRB 221202A: Swift detection of a burst
  88. Swift GRB221202.84: Global MASTER-Net observations report
  89. GCN: GRB 221201A: Swift/UVOT Upper Limits
  90. GRB 221201A: Swift-XRT refined Analysis
  91. GRB 221201A: Enhanced Swift-XRT position
  92. Swift GRB 221201A: Global MASTER-Net observations report
  93. Konus-Wind detection of GRB 221124A
  94. GRB 221201A: Swift detection of a burst
  95. GRB 221201A: Fermi GBM Final Real-time Localization
  96. Fermi Gamma-ray Burst Monitor trigger 691534074/221130867 is not a GRB
  97. Optical polarization observation of GRB 221009A
  98. GRB 221126A: Fermi GBM observation
  99. IceCube-221124A: Upper limits from a search for additional neutrino events in IceCube
  100. GRB 221126A: AGILE detection

Advanced

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